Question: Simplify the following expression: $q = \dfrac{7}{10p} + \dfrac{4}{9p}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $10p$ and $9p$ $\lcm(10p, 9p) = 90p$ $ q = \dfrac{9}{9} \cdot \dfrac{7}{10p} + \dfrac{10}{10} \cdot \dfrac{4}{9p} $ $q = \dfrac{63}{90p} + \dfrac{40}{90p}$ $q = \dfrac{63 +40}{90p}$ $q = \dfrac{103}{90p}$